This invention relates generally to wireless communication systems. More particularly, this invention relates to cellular telephones capable of radio and cellular communication at substantially the same time.
Consumers desire communication equipment having greater flexibility and more options for use with existing communication systems. In recent years, Family Radio Service (FRS) has gained in popularity. FRS is a short distance, two-way personal radio service. In a typical FRS system, there are two or more hand-held radio communicators. Each radio communicator has a transceiver, which operates in half duplex mode, at xc2xd watt or less, and within a particular UHF frequency band.
FRS enables members of a group to communicate with other members of the group who are out of speaking range but are within the same general area. Campers, hikers, cyclists, and other outdoor enthusiasts use FRS to keep in contact with one another. Parents use FRS to keep in touch with children playing in the neighborhood. Families or friends use FRS to keep in contact with one another while at shopping malls, sporting events, and similar activities.
FRS is suitable for group members to communicate with one another when they are in the same general area. However, FRS is not suited for communication beyond the general area and with cellular communication systems. FRS transceivers have a range of less than one half mile and operate in a frequency band incompatible with cellular communication. Moreover, FRS operates in half duplex mode, whereas cellular telephones operate in full duplex mode.
To communicate beyond the general area or with a cellular system, one FRS group member must make a cellular phone call while in radio communication with other FRS members. However, the other members cannot participate in the cellular call directly. They cannot make the cellular call; the person using the cellular telephone must do it for them. Everyone must relay messages through the member using the cellular telephone. In addition, one of the FRS group members must carry the cellular telephone.
Accordingly, there is a need for a cellular telephone permitting radio and cellular communication.